More than a dozen comfort dogs from states across America have been drafted in to provide emotional support to survivors, loved ones and emergency service workers following the murder of 49 people at Pulse nightclub in the early hours of Sunday.

The dogs have been stationed outside hospitals, police stations, community centres and churches wearing vests that read "Please Pet Me."

"They help people relax and calm down," Tim Hetzner, president of the LCC Comfort Dogs, tells ABC News.

"Your blood pressure goes down when you pet a dog, you feel more comfortable, and people end up talking," Hetzner adds. "They're good listeners, they're non-judgmental, they're confidential."

Comfort Dogs and their handlers are in ‪Orlando‬ to support victims

Hetzner set up the programme with just four dogs eight years ago and now has more than 100 comfort dogs working in 23 states across the US. They have provided support to victims of the Sandy Hook Shooting and Boston Marathon attacks, ABC News reports.

More dogs will be deployed to Orlando than any other incident following the deadliest mass shooting in modern US history.